Third party libraries and frameworks typically have to support a range of software platform versions, generally going several versions back. This frequently means that the developers often do not take advantage of features available in newer versions of the software platforms because it is often difficult to express conditional platform dependencies (i.e., reflectively test for and invoke methods that might not be present in all supported platform versions). Alternatively, it may be expensive (e.g., in development time and distribution media) to distribute multiple library versions in order to support different underlying platform versions. This may create disincentives for library and framework developers use new features, which in turn may be a disincentive for users to upgrade to new platform versions, itself creating a disincentive for developers to support features of newer platform versions—a circle that may impedes adoption of new features and improvements.
Software platforms are generally versioned in a backward compatible manner, such that older applications may be able run on newer platform versions. However, software libraries frequently have a dependency on a certain version of an underlying platform. Thus, library developers may desire to have libraries run on older platform versions, yet may also desire to use features from newer platform versions. Thus, software libraries developers frequently delay using newer platform features until they can require the newer platform version (and therefore may not be backward compatible with older platform versions). Alternatively, developers of software libraries may distribute multiples version of a library in order to be both backward compatible for some users and support newer platform features for others.